A fan rotor dynamic balancing weight assembly method

Abstract

The application discloses a fan rotor dynamic balance weight assembly method, which adopts rabbit ear type locking to prevent the fan rotor dynamic balance weight from falling. The assembly method comprises the following steps: reserving a circular ring-shaped protrusion coaxial with an inner circular surface at a large hole in an end surface of a first-stage integral blade disc of a fan rotor, and reserving a plurality of circular through holes on the surface of the circular ring-shaped protrusion; selecting a balance weight with a concave shape and assembling the balance weight on the circular ring-shaped protrusion by using the concave groove and aligning the circular through holes; adopting rabbit ear type locking pieces and bolts to fasten the balance weight on the circular ring-shaped protrusion, and then respectively bending fixing claws on the rabbit ear type locking pieces to the bolts and positioning claws to the balance weight to prevent the balance weight from rotating in the axial direction and the radial direction; and finally, tightening the bolts to complete the assembly. The application is convenient to operate, the balance weight is reliably assembled and not easy to fall off, and does not substantially affect the structure and strength of the fan rotor itself.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine assembly technology, specifically relating to a method for assembling a dynamic balancing counterweight for a fan rotor, particularly a method using a rabbit-ear locking mechanism to prevent the dynamic balancing counterweight from falling off. Background Technology

[0002] Aircraft engine fan rotors need to be balanced after assembly. Due to differences in internal structure and dimensional tolerances of the parts, imbalance can easily occur, necessitating the addition of counterweights. During the assembly of these counterweights, the assembly method must be carefully controlled to prevent them from detaching and damaging the engine during high-speed rotation. When the fan rotor rotates at high speed, the uneven mass distribution of the disc generates varying centrifugal forces. This imbalance causes fan rotor vibration, noise, and negatively impacts the overall engine performance and lifespan. Summary of the Invention

[0003] The present invention aims to provide a method for assembling dynamic balancing counterweights for a fan rotor, which is convenient to operate, ensures reliable assembly of the balancing counterweights, prevents them from falling off, and does not have a substantial impact on the structure and strength of the fan rotor itself.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for assembling a dynamic balancing counterweight for a fan rotor includes: Step 1: On the inner circular surface of the large hole on the end face of the first stage integral bladed disk of the fan rotor, a ring-shaped protrusion coaxial with the inner circular surface is reserved. Multiple circular through holes are reserved on the surface of the ring-shaped protrusion. The axes of the multiple circular through holes are parallel to the axis of the first stage integral bladed disk, and the multiple circular through holes are distributed on the circumference with the center of the first stage integral bladed disk as the center. Step 2: Select a counterweight block with a U-shaped shape. On each of the two parallel sidewalls on both sides of the U-shaped groove, there is a through hole. The two through holes are coaxial. One of the through holes has an internal thread. Move the counterweight block along the radial direction of the first-stage integral impeller towards the annular protrusion on the inner circular surface of the large hole on the end face of the first-stage integral impeller until the annular protrusion is embedded in the groove of the counterweight block. Then slide the counterweight block along the circumference of the annular protrusion until the two through holes on the counterweight block are aligned with one circular through hole on the annular protrusion. Step 3: Select a rabbit ear-type locking plate containing two fixing claws and one positioning claw. Attach the rabbit ear-type locking plate to the side wall end face of the unthreaded through hole on the counterweight block, ensuring that the locking plate hole of the rabbit ear-type locking plate is aligned with the opening of the through hole. Then, use bolts to sequentially insert into the locking plate hole of the rabbit ear-type locking plate, the opening of the unthreaded through hole, the circular through hole, and finally connect it to the threaded through hole. The bolt head has an external hexagonal structure. Step 4: Bend the two fixing claws of the rabbit ear-shaped locking plate until the two fixing claws are respectively attached to different side planes of the hexagonal structure on the bolt head; Step 5: Bend the positioning claw of the rabbit ear-shaped lock plate until the positioning claw fits against the outer surface of the groove bottom on the counterweight block.

[0005] Alternatively, in step one, a machining center or milling machine is used to machine multiple circular through holes on the annular protrusion surface of the large hole on the end face of the first-stage integral impeller.

[0006] Alternatively, in step one, the radius of the circumference of the multiple circular through holes is equal to the radius of the large hole on the end face of the first-stage integral bladed disk + 7.5 mm.

[0007] Alternatively, in step three, the two fixing claws of the rabbit ear-shaped locking plate are perpendicular to the positioning claw.

[0008] As an option: In step four, after the two fixing claws are attached to different side planes of the hexagonal structure of the bolt head, the gap between the fixing claws and the side planes is not greater than a preset value. In step five, after the positioning claw is attached to the outer surface corresponding to the bottom of the groove on the counterweight block, the gap between the positioning claw and the outer surface is not greater than a preset value.

[0009] As an option: In step four, the bends of the two fixing claws are transitioned by an arc and without cracks; In step five, the bend of the positioning claw is transitioned by an arc and there are no cracks.

[0010] Alternatively, in step five, the positioning claw is not allowed to be bent in advance, and a force that stretches the positioning claw is always applied to the end of the positioning claw during the bending process.

[0011] Alternatively, after step five, a feeler gauge is used to check the fit gap between the rabbit ear-shaped locking plate and the side wall end face where the unthreaded through hole on the counterweight is located. If the gap exceeds the preset value, the bolt is tightened.

[0012] Furthermore, the torque used to tighten the bolts is controlled between 3 N·m and 5 N·m.

[0013] Compared with existing technologies, this invention employs a U-shaped counterweight, a rabbit-ear-type locking plate containing two fixing claws and one positioning claw, and a bolt with an outward hexagonal head forming an assembly relationship at a circular through-hole on the annular protrusion on the inner circular surface of the large hole on the end face of the first-stage integral bladed disk. This satisfies the dynamic balance requirements of the aircraft engine fan rotor, and the assembled counterweight is effectively locked. The fixing claws of the rabbit-ear-type locking plate prevent axial rotation, and the positioning claws prevent radial rotation. The fan rotor dynamic balance counterweight assembly method of this invention is convenient to operate, the counterweight assembly is reliable, and it is not easy to fall off. Furthermore, since the annular protrusion and circular through-hole, which are machined to be coaxial with the inner circular surface, do not bear large loads and centrifugal forces, they will not have a substantial impact on the strength and structure of the fan rotor. Attached Figure Description

[0014] Figure 1 A schematic diagram showing the pre-reserved annular protrusion and circular through hole on the inner circular surface of the large hole of the first-stage integral bladed disk. Figure 2 A schematic diagram of a bolt with an outward hexagonal head; Figure 3 A schematic diagram showing the tensioning and bending of the positioning claws on the rabbit ear-type lock plate; Figure 4 This is a schematic diagram showing the bent and fitted fixing claws of the rabbit ear-shaped locking plate; Figure 5 A schematic diagram for checking the axial clearance between the rabbit ear-type locking plate and the counterweight; In the diagram: 1- counterweight, 2- circular through hole, 3- bolt, 4- bent rabbit ear-shaped locking plate, 5- fixing claw, 6- positioning claw. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0016] Aircraft engines are expensive, and parts are prone to detachment during high-speed rotation due to loose assembly. The counterweights of the fan rotor are not very strong, so controlling their assembly process is key to preventing them from falling off.

[0017] To address the above problems, the present invention adopts the following solution: 1. For example Figure 1 As shown, at the inner circular surface of the large hole on the end face of the first-stage integral impeller of the fan rotor ( Figure 1The right end face of the first-stage integral bladed disk has a large end hole. A ring-shaped protrusion coaxial with the inner circular surface is reserved. Thirty circular through holes 2 with a diameter of 5.5mm are machined on the ring-shaped protrusion. The circular through holes 2 can be machined using a machining center / milling machine. During machining, the center position of the circular through holes should meet the following requirements: The distance from the center of the circular through hole 2 to the center of the first-stage integral impeller is [(inner diameter of the large hole on the end face of the first-stage integral impeller + 15) / 2] mm.

[0018] 2. The counterweight 1 is assembled at the annular protrusion on the right end face of the first-stage integral bladed disk, such as... Figure 5 The counterweight 1 is U-shaped, and there is a through hole on each of the two parallel sidewalls of the groove corresponding to the U-shape. One of the through holes has an internal thread structure on its inner wall, which is used to cooperate with the bolt 3 to achieve initial locking of the counterweight 1. The other through hole has a smooth inner wall.

[0019] 3. For example Figure 2 Bolt 3 is a hexagonal structure. The six side planes on the hexagonal structure make it easy to tighten. The size of bolt 3 is MJ5×0.8mm.

[0020] 4. For example Figure 3 A rabbit-ear type locking plate 4 with two fixing claws 5 is selected. The two fixing claws 5 are used to fasten the two adjacent side planes on the hexagonal head of the bolt 3. See Figure 4 and Figure 5 (Only one fixed claw 5 is shown in the figure) to prevent the axial rotation of the counterweight 1.

[0021] 5. The positioning claw 6 of the rabbit ear-shaped locking plate 4 is used. The tail edge of the positioning claw 6 is bent at a 90-degree angle to secure the plane of the counterweight 1 (this plane corresponds to the outer plane of the bottom of the U-shaped groove). Figure 3 The middle bends in the direction of closeness Figure 4 This state prevents the radial rotation of the counterweight 1.

[0022] 6. When bending the rabbit ear-style lock plate 4, use a magnifying glass to check the bend. Figure 3 The middle bends in the direction of closeness Figure 4 In the condition where the fixing claw 5 and the positioning claw 6 are bent, they should be close to the head plane of the bolt 3 and the outer surface of the counterweight 1 respectively (the gap should not be greater than 0.08mm). Visual inspection should be performed, and the bending points of the fixing claw 5 and the positioning claw 6 should be connected by an arc. It is not allowed to strike the tail edge of the positioning claw 6 to prevent cracks.

[0023] 7. Before installation, the positioning claw 6 of the rabbit ear type locking plate 4 must not be pre-bent. When bending the positioning claw 6 of the rabbit ear type locking plate 4, the positioning claw 6 of the rabbit ear type locking plate 4 should always be pulled taut in the direction of elongating the positioning claw 6.

[0024] 8. After the rabbit ear-type locking plate 4 is tightened, use a feeler gauge to check the axial clearance between the rabbit ear-type locking plate 4 and the counterweight 1 (e.g., Figure 5 (At points A and B), the gap should not exceed 0.05mm.

[0025] 9. If the axial gap between the rabbit ear-type locking plate 4 and the counterweight 1 is too large, tighten the bolt 3, and control the tightening torque between 3 N·m and 5 N·m.

[0026] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for assembling a dynamic balancing counterweight for a fan rotor, characterized in that, include: Step 1: A ring-shaped protrusion coaxial with the inner circle is reserved on the inner circle of the large hole on the end face of the first stage integral bladed disk of the fan rotor. Multiple circular through holes (2) are reserved on the surface of the ring-shaped protrusion. The axis of the multiple circular through holes (2) is parallel to the axis of the first stage integral bladed disk, and the multiple circular through holes (2) are distributed on the circumference with the center of the first stage integral bladed disk as the center. Step 2: Select a counterweight (1) with a U-shaped shape. On each of the two parallel sidewalls on both sides of the U-shaped groove, there is a through hole. The two through holes are coaxial. One of the through holes has an internal thread. Move the counterweight (1) along the radial direction of the first-stage integral bladed disk and toward the annular protrusion on the inner circular surface of the large hole on the end face of the first-stage integral bladed disk until the annular protrusion is embedded in the groove of the counterweight (1). Then slide the counterweight (1) along the circumference of the annular protrusion until the two through holes on the counterweight (1) are aligned with one circular through hole (2) on the annular protrusion. Step 3: Select a rabbit ear-shaped locking plate (4) containing two fixing claws (5) and one positioning claw (6). Place the rabbit ear-shaped locking plate (4) on the side wall end face of the unthreaded through hole on the counterweight block (1) and ensure that the locking plate hole of the rabbit ear-shaped locking plate (4) is aligned with the opening of the through hole. Then, use a bolt (3) to sequentially insert the locking plate hole of the rabbit ear-shaped locking plate (4), the opening of the unthreaded through hole, and the circular through hole (2) and connect it to the through hole with internal threads. The head of the bolt (3) is an external hexagonal structure. Step 4: Bend the two fixing claws (5) of the rabbit ear-shaped locking plate (4) until the two fixing claws (5) are respectively attached to different side planes of the hexagonal structure on the head of the bolt (3); Step 5: Bend the positioning claw (6) of the rabbit ear-shaped lock plate (4) until the positioning claw (6) fits against the outer surface of the groove bottom on the balance weight block (1).

2. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step one, multiple circular through holes (2) are machined on the annular protrusion surface of the large hole on the end face of the first-stage integral bladed disk using a machining center or milling machine.

3. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step one, the radius of the circumference of the multiple circular through holes (2) is equal to the radius of the large hole on the end face of the first-stage integral bladed disk + 7.5 mm.

4. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step three, the two fixing claws (5) of the rabbit ear-shaped locking plate (4) are perpendicular to the positioning claws (6).

5. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step four, after the two fixing claws (5) are attached to different side planes of the hexagonal structure of the bolt head (3), the gap between the fixing claws (5) and the side planes is not greater than the preset value. In step five, after the positioning claw (6) fits against the outer surface corresponding to the bottom of the groove on the counterweight block (1), the gap between the positioning claw (6) and the outer surface is not greater than a preset value.

6. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step four, the bends of the two fixing claws (5) are transitioned by an arc and without cracks; In step five, the bend of the positioning claw (6) is transitioned by an arc and without cracks.

7. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: In step five, the positioning claw (6) is not allowed to be bent in advance, and during the bending of the positioning claw (6), a force is always applied to the end of the positioning claw (6) to stretch it.

8. The assembly method of a fan rotor dynamic balancing counterweight according to claim 1, characterized in that: After step five, use a feeler gauge to check the fit gap between the rabbit ear lock plate (4) and the side wall end face where the through hole without internal thread is located on the counterweight (1). If the gap exceeds the preset value, tighten the bolt (3).

9. The assembly method of a fan rotor dynamic balancing counterweight according to claim 8, characterized in that: The torque when tightening the bolt (3) is controlled between 3 N·m and 5 N·m.

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